Function based dynamic traffic management for network services

ABSTRACT

Technologies are disclosed for local and distributed function based dynamic traffic management for network services. A service host executes a network service and provides a service framework that includes one or more handlers. When a request is received for the service, one of the handlers assigns a classification to the request. The handler then provides the classification to a dynamic function based traffic controller. The controller determines whether the network service is to process the request based on the classification of the request, metrics associated with the network service, and a local traffic management policy. If the controller determines that the network service is not to process the request, the request is rejected. Otherwise, the request is passed to the network service for processing. Metrics can also be provided from the service host to a distributed performance monitoring system for use in managing network traffic at a fleet level.

BACKGROUND

One approach to throttling requests made to network services involvesspecifying the maximum number of requests per second, or other timeperiod, that are permitted to be made to the network service. Anyrequests that are received in excess of the specified maximum number ofrequests in a given time period are throttled (i.e. rejected). Thismechanism is sometimes referred to as “static throttling.”

The static throttling mechanism described above suffers from severaldrawbacks. For example, the operator of a network service might not havecontrol over all of the processes that are executed on the service hostcomputer utilized to execute a network service. For instance, theoperator might not have control over the periodic execution ofmaintenance tasks on the service host. These maintenance tasks consumecentral processing unit (“CPU”) cycles, memory, and, potentially, otherresources that might otherwise be available for use by the networkservices.

A network service operator might, therefore, specify the maximum numberof requests that are permitted to be made to a network service in agiven time period pessimistically in view of the possibility that otherprocesses might utilize CPU cycles, memory, or other resources of theservice host, even though the other processes might only be executedperiodically. As a result, the true capacity of a network service toprocess requests might not be realized.

It is with respect to these and other considerations that the disclosuremade herein is presented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a network services architecture diagram showing aspects of amechanism disclosed herein for local function based dynamic trafficmanagement for network services, according to one configurationpresented herein;

FIG. 2 is a flow diagram showing a routine that illustrates aspects ofthe operation of the mechanism shown in FIG. 1 for local function baseddynamic traffic management for network services, according to oneconfiguration presented herein;

FIG. 3 is a network services architecture diagram showing aspects of amechanism disclosed herein for distributed function based dynamictraffic management for network services, according to one configurationpresented herein;

FIG. 4 is a flow diagram showing a routine that illustrates aspects ofthe operation of the mechanism shown in FIG. 3 for distributed functionbased dynamic traffic management for network services, according to oneconfiguration presented herein;

FIG. 5 is a graphical user interface diagram showing aspects of theconfiguration of one illustrative graphical user interface disclosedherein for defining a local or distributed traffic management policy,according to one configuration disclosed herein;

FIG. 6 is network diagram showing aspects of a distributed computingenvironment in which the configurations presented herein can beimplemented;

FIG. 7 is a network diagram illustrating aspects of a data center thatcan be utilized to implement the various technologies presented herein;and

FIG. 8 is a computer architecture diagram showing one illustrativecomputer hardware architecture for implementing a computing device thatcan be utilized to implement aspects of the various configurationspresented herein.

DETAILED DESCRIPTION

The following detailed description is directed to technologies for localand distributed function based dynamic traffic management for networkservices. Through an implementation of the technologies describedherein, requests made to network services can be throttled based uponboth the type of the request and real time metrics obtained from thenetwork service and/or the network service host. In this way, servicerequests can be throttled based upon the actual utilization of computingresources (e.g. CPU cycles and random access memory (“RAM”)) on theservice host rather than upon a statically defined request limit.Consequently, operation of the service host can be optimized to maximizethe number of requests handled by the service host. Moreover, becauserequests are throttled based up actual real time metrics describing thestate of computing resources on the service host, network services canbe configured to operate more reliably by throttling incoming requestswhen the utilization of particular resources reaches a specified level.Technical benefits other than those specifically disclosed above canalso be realized through implementations of the technologies disclosedherein.

In one particular implementation, a mechanism is provided for localfunction based dynamic traffic management for network services (whichmight be referred to herein simply as “services” or “a networkservice”). In order to utilize this mechanism, a graphical userinterface (“GUI”) is provided in one configuration through which aservice operator can define a local network traffic management policy.The local network traffic management policy defines parameters that areutilized to throttle traffic directed to a network service executing ona service host.

In one specific configuration, the local network traffic managementpolicy is a local service traffic management function. The local servicetraffic management function is a polynomial function that takes as inputthe value of one or more metrics relating to a locally executing networkservice (e.g. CPU utilization, memory utilization, etc.), and providesas output a throttle rate for a particular classification of servicerequests. The throttle rate defines the rate at which service requestshaving a particular classification are to be throttled.

In this configuration, the GUI provides a user interface element throughwhich a service operator or other user can define a curve representingthe local service traffic management function. The user can be permittedto provide control points for the curve, to “drag” the control points todefine the curve, and to specify the contour of the curve in differentways. The GUI can also provide functionality for specifying otherproperties of a local service traffic management function and/or forviewing the real time metrics described above. Other mechanisms can alsobe provided for permitting the definition of a local service trafficmanagement function.

In one configuration, a service framework also executes on the servicehost computer executing the service. The service framework providesvarious types of functionality to the network service, including theability to execute one or more handlers. When multiple handlers arespecified for use, the handlers can be executed in a specified order.The ordered collection of handlers utilized in a particular serviceframework might be referred to herein as a “handler chain.”

Each handler in a handler chain can perform different types ofprocessing on a service request. For example, a handler might addmetadata to the request for use by subsequent handlers in a handlerchain. Other types of processing might also be performed. When the lasthandler in the handler chain has completed its processing, the requestcan be passed to the network service for processing. When the networkservice has completed its processing of the request, a response can bepassed back up the service chain to the service client that made theinitial request in a similar fashion.

In one configuration, a handler in the service chain executing within aservice framework enables functionality for local function based trafficmanagement. In particular, a handler can receive a service request anddetermine a classification for the request based upon various types ofinformation. For example, and without limitation, the classification canbe determined based upon attributes of the original request or uponmetadata added to the request by previous handlers in the handler chain.Other types of data can also be utilized to assign a classification tothe request.

Once a service request has been classified, the classification can beutilized, along with other information, to determine if the servicerequest is to be throttled (i.e. rejected). For example, and withoutlimitation, in one configuration the classification is provided to adynamic function based traffic controller executing on the service host.The dynamic function based traffic controller is a software componentthat is configured to determine whether a request is to be throttledbased upon the associated classification, the local traffic managementpolicy described above, and one or more metrics associated with thenetwork service (e.g. CPU utilization, cache hit/miss rate, memoryutilization, etc.).

The dynamic function based traffic controller can obtain the metrics inreal time from a local real time performance monitoring system alsoexecuting on the service host in one particular configuration. The localreal time performance monitoring system can be configured to executemodules that generate the metrics by periodically sampling differentresources provided by the service host and/or the network service. Therate at which the metrics are sampled can be predefined by an owner oroperator of the network service. Different sampling rates can also bespecified for different resources. For example, a metric relating to CPUutilization might be sampled at a different rate than a metric relatingthe memory utilization. The collected metrics can be stored and madeavailable to the dynamic function based traffic controller in real ornear-real time.

If the dynamic function based traffic controller determines that theservice request is to be throttled, the request is rejected and aresponse message may be routed up the handler chain in the mannerdescribed above to the service client that transmitted the originalservice request. If the dynamic function based traffic controllerdetermines that the service request is not to be throttled, the requestcan be provided to the next handler in the handler chain or directly tothe network service if the handler performing the throttling is the lasthandler in the handler chain.

In another configuration, a mechanism similar to that described abovecan be utilized to perform distributed function based dynamic trafficmanagement. In this configuration, a distributed traffic managementpolicy can be defined utilizing a GUI similar to that described above.The distributed traffic management policy defines how service requestsare to be throttled on a fleet-wide basis. In order to evaluate thedistributed traffic management policy, metrics are collected from thenetwork service host computers in a host fleet by a distributedperformance monitoring system. The metrics can be collected in real orin near-real time as with the locally collected metrics described above.

A distributed function based traffic controller utilizes the distributedtraffic management policy and the metrics provided by the distributedperformance monitoring system to determine on a fleet-wide level whetherto throttle certain types of service requests. If requests are to bethrottled, the distributed function based traffic controller can sendupdate events to the service hosts in the fleet instructing the servicehosts to adjust the throttle rate for certain classifications ofrequests. The throttle rate can then be utilized in the manner describedabove to throttle incoming requests to each service host in the fleet.Additional details regarding the various components and processesdescribed briefly above for function based dynamic traffic managementfor network services will be presented below with regard to FIGS. 1-8.

It should be appreciated that the subject matter presented herein can beimplemented as a computer process, a computer-controlled apparatus, acomputing system, or an article of manufacture, such as acomputer-readable storage medium. While the subject matter describedherein is presented in the general context of program modules thatexecute on one or more computing devices, those skilled in the art willrecognize that other implementations can be performed in combinationwith other types of program modules. Generally, program modules includeroutines, programs, components, data structures, and other types ofstructures that perform particular tasks or implement particularabstract data types.

Those skilled in the art will also appreciate that aspects of thesubject matter described herein can be practiced on or in conjunctionwith other computer system configurations beyond those described herein,including multiprocessor systems, microprocessor-based or programmableconsumer electronics, minicomputers, mainframe computers, handheldcomputers, personal digital assistants, e-readers, cellular telephonedevices, special-purposed hardware devices, network appliances, and thelike. The configurations described herein can be practiced indistributed computing environments, where tasks are performed by remoteprocessing devices that are linked through a communications network. Ina distributed computing environment, program modules can be located inboth local and remote memory storage devices.

In the following detailed description, references are made to theaccompanying drawings that form a part hereof, and that show, by way ofillustration, specific configurations or examples. The drawings hereinare not drawn to scale. Like numerals represent like elements throughoutthe several figures (which might be referred to herein as a “FIG.” or“FIGS.”).

FIG. 1 is a network services architecture diagram showing aspects of amechanism disclosed herein for local function based dynamic trafficmanagement for network services, according to one configurationpresented herein. As shown in FIG. 1, and described briefly above, aservice host computer 102 (which might be referred to herein simply as a“service host”) executes a network service 104. The network service 104can provide different types of functionality to remote clients, such asthe service client 106, via remote service calls. The service hostcomputer 102 and the service client 106 can be implemented using tower,rack-mount, or blade server computers, or using another type ofcomputing device configured in the manner described herein to processservice requests.

In one configuration, the service client 106 submits service requests tothe network service 104 utilizing the Hypertext Transfer Protocol(“HTTP”). In the example shown in FIG. 1, for instance, the serviceclient 106 has submitted the HTTP request 108 to the network service 104executing on the service host computer 102. The HTTP request 108 caninclude headers and a data payload for consumption by the networkservice 104. For example, the HTTP request 108 might request that thenetwork service 104 perform a specified processing task and return aresponse to the calling service client 106. The processing taskperformed by the network service 104 might include, but is not limitedto, performing a computational task, retrieving data, and/or other typesof functionality. In this regard, it should be appreciated that themechanisms described herein are not dependent upon the particularfunctionality provided by the network service 104. It should also beappreciated that network protocols other than HTTP can be utilized tosubmit requests to the network service 104 in other configurations.

As also shown in FIG. 1 and described briefly above, the service hostcomputer 102 also executes a service framework 110 in one particularconfiguration. The service framework 110 provides various types offunctionality to the network service 104, including the ability toexecute one or more handlers 116A-116C (which might be referred toherein collectively as “handlers 116” or singularly as “a handler 116”).When multiple handlers 116 are specified for use, the handlers 116 canbe executed in an order specified by the owner or operator of thenetwork service 104. As mentioned above, the ordered collection ofhandlers 116 utilized in a particular service framework 110 might bereferred to herein as a “handler chain.”

In one particular configuration, the service framework 110 is configuredto convert incoming service requests, such as the HTTP request 108, intoprotocol-agnostic data structures referred to herein as “jobs.” Forinstance, in the example shown in FIG. 1, the service framework 110 hasconverted the HTTP request 108 into a job 112. The job 112 includes data(referred to herein as “request attributes 114”) from the original HTTPrequest 108. For example, the request attributes 114 can include theheaders, source and destination network addresses, the payload, and/orany other information contained in the original HTTP request 108. Inthis manner, the handlers 116 in the service chain can process servicerequests without understanding the specifics of a particular transportprotocol, such as HTTP. In this regard, it should be appreciated thatthe mechanisms disclosed herein are not limited to such animplementation, and that the technologies disclosed herein can beutilized without converting incoming service requests to jobs.Accordingly, the terms “job,” “request,” and “service request” may beused interchangeably herein.

As mentioned above, each handler 116 in a handler chain can inspect thecontents of a job 112 and perform different types of processing on thejob 112. For example, and without limitation, a handler 116A might addmetadata 118 to a job 112. The metadata 118 can be utilized bysubsequent handlers 116 in a handler chain or by the network service104. Other types of processing might also be performed.

One example of the functionality that can be provided by a handler 116is classifying a service request as being generated by a human or by anon-human initiated process (which might be referred to herein as a“robot” or “bot”). Such a handler 116 might write metadata 118 to thejob 112 specifying the computed probability that the request wasoriginated by a human or a bot. Another handler 116 might write metadata118 to the job 112 specifying the identity of a user associated with theservice request. As will be discussed in detail below, decisions as towhether to throttle (i.e. reject) a particular service request can bemade based upon the metadata 118 written to a job 112 by one or more ofthe handlers 116.

Each handler 116 in a handler chain can also reject a particular job 112or allow the job 112 to continue on to subsequent handlers 116 in thehandler chain. When the last handler 116 in a handler chain (i.e. thehandler 116C in the example shown in FIG. 1) has completed itsprocessing, the job 112 can be passed to the network service 104 forprocessing. When the network service 104 has completed its processing ofthe job 112, a response can be passed back up the service chain to theservice client 106 that made the initial request (i.e. the HTTP request108 shown in FIG. 1) in a similar fashion. In the example shown in FIG.1, an HTTP response 144 has been transmitted to the service client 106.

In one configuration, a handler 116 in the service chain executingwithin the service framework 110 enables functionality for localfunction based traffic management. In particular, and as discussedbriefly above, a handler 116B can receive a job 112 and determine aclassification 122 for the job 112 based upon various types ofinformation. For example, and without limitation, the classification 122can be determined based upon the request attributes 114 included in thejob 112 from the original HTTP request 108. The classification 122 canalso be made based upon the metadata 118 added to the request byprevious handlers 116 in the handler chain. Other types of data can alsobe utilized to assign a classification 122 to a service request.

The handler 116B that is configured to provide the service trafficmanagement functions disclosed herein can be positioned at any point inthe handler chain. It should be appreciated, however, that it might bedesirable to position the handler 116B closer to the service client 106(i.e. closer to the beginning of the handler chain) in order to avoidthe performance of unnecessary work by previous handlers 116 in thehandler chain in the event that a request is throttled. Any handlers 116that add or modify metadata 118 that the handler 116B utilizes forclassification will, however, need to be located prior to the handler116B in the handler chain.

In the example configuration shown in FIG. 1, a traffic classifier 120examines the metadata 118 and/or the request attributes 114 to determinea classification 122 for the job 112. In the example discussed abovewherein the metadata 118 specifies a probability that the request wasgenerated by a bot, the classification 122 might for example indicatethat the request was generated by a bot or by a human. Other types ofclassifications 122 can also be assigned to a job 112. For example, andwithout limitation, a job 112 can be classified based upon the size ofthe job 112, the amount of computing resources expected to be consumedduring processing of the job 112, and/or other factors. Additionally,multiple classifications 122 can also be assigned to the same job 112.

Once a service request has been classified, the classification 122 canbe utilized, along with other information, to determine if the servicerequest is to be throttled (i.e. rejected). For example, and withoutlimitation, in one configuration the traffic classifier 120 provides theclassification 122 to a traffic controller client 124. The trafficcontroller client 124 is configured to interoperate with a dynamicfunction based traffic controller 126, also executing on the servicehost computer 102. The dynamic function based traffic controller 126 isa software component that is configured to determine whether a servicerequest is to be throttled based upon the associated classification 122,the local traffic management policy 130 described briefly above, and oneor more metrics 132 associated with the network service 104 (e.g. CPUutilization, cache hit/miss rate, memory utilization, etc.). Additionaldetails regarding this process are provided below.

In order to utilize the mechanism shown in FIG. 1, a policy definitiontool 128 is provided in one particular configuration. The policydefinition tool 128 is a software component configured to provide a GUIthrough which a user, such as the operator of the network service 104,can define the local network traffic management policy 130. As mentionedabove, the local network traffic management policy 130 definesparameters that are utilized by the dynamic function based trafficcontroller 126 in one configuration to throttle service requestsdirected to the network service 104.

In one specific configuration, the local network traffic managementpolicy 130 is a local service traffic management function. The localservice traffic management function is a polynomial function that takesas input the value of one or more metrics 132 relating to the locallyexecuting network service 104 (e.g. CPU utilization, memory utilization,etc.), and provides as output a throttle rate for a particularclassification 122 of service requests. The throttle rate defines therate at which service requests having a particular classification 122are to be throttled.

In this configuration, the GUI provided by the policy definition tool128 includes a user interface element through which a service operatoror other user can define a curve representing the local service trafficmanagement function. The user can be permitted to provide control pointsfor the curve, to “drag” the control points to define the curve, and tospecify the contour of the curve in different ways. The GUI can alsoprovide functionality for specifying other properties of a local servicetraffic management function and/or for viewing the real time metrics 132described above.

It should be appreciated that the policy definition tool 128 can beimplemented as a web application hosted by the service host computer 102or another computer system. The policy definition tool 128 can also beimplemented as a stand-alone application capable of connecting to theservice host computer 102 in other configurations. Additional detailsregarding the operation of the policy definition tool 128 and anillustrative GUI for defining a local service traffic managementfunction will be provided below with regard to FIG. 5.

It should also be appreciated that other mechanisms can also be utilizedin other configurations for defining the local network trafficmanagement policy 130. For example, a management console, command lineinterface (“CLI”), configuration file, or network service applicationprogramming interface (“API”) can be utilized to define the localtraffic management policy 130 and to provide the local trafficmanagement policy 130 to the dynamic function based traffic controller126 in other configurations.

As mentioned briefly above, the dynamic function based trafficcontroller 126 can obtain the metrics 132 in real or near-real time froma local real time performance monitoring system 134, also executing onthe service host computer 102 in one particular configuration. The localreal time performance monitoring system 134 can be configured to executemodules 136A-136C that generate the metrics 132 by periodically (e.g.every 500 ms) sampling different resources provided or utilized by theservice host computer 102 and/or the network service 104. For example,and without limitation, a module 136A might sample data indicating theutilization of one or more CPUs of the service host computer 102.Another module 132B might sample data indicating the amount of RAM beingutilized by a virtual machine (“VM”) instance executing on the servicehost computer 102. As discussed briefly above, the sampling rate can bepredefined by an owner or operator of the network service. Differentsampling rates can also be specified for different resources. Forexample, a metric relating to CPU utilization might be sampled at adifferent rate than a metric relating the memory utilization.

The samples 138A-138C generated by the modules 136A-136C can includedata identifying the particular feature that was sampled, a valuedescribing the state of the feature, and a timestamp indicating the timeand/or date that the sample 138 was taken. The samples 138A-138C caninclude other information in other configurations.

The local real time performance monitoring system 134 can process thesamples 138A-138C collected by the modules 136A-136C, respectively, indifferent ways to generate the metrics 132. For example, variousfunctions can be applied to the samples 136A-136C, such as a blendingfunction, a smoothing function or an averaging function, in order togenerate the metrics 132. The metrics 132 can then be stored, such as inthe local host metrics data store 140 in the configuration shown in FIG.1, and made available to the dynamic function based traffic controller126 in real or near-real time. In one configuration, the local hostmetrics data store 140 is an in-memory database of time series data fora particular metric 132 for a particular time period (e.g. the previousten seconds). Various types of APIs can be exposed for enablingcommunication between the local real time performance monitoring system134 and the dynamic function based traffic controller 126.

The modules 136 can also be configured to obtain metrics 132 from thenetwork service 104. For example, and without limitation, the metrics132 can describe the number of a particular type of operation performedby the network service 104 within a particular time period (e.g. thenumber of requests to a certain method within the last ten seconds). Asanother example, a metric 132 might describe the number of databaseconnections that the network service 104 currently has open. In thisregard, it should be appreciated that the modules 136 are pluggable, andthat the particular modules 136 that are utilized can be defined by theoperator of the network service 104 in one particular configuration.

The dynamic function based traffic controller 126 can utilize the localtraffic management policy 130, the classification 122, and the metrics132 to determine if a request is to be throttled. The dynamic functionbased traffic controller 126 returns a Boolean value (e.g. Yes or No) tothe traffic controller client 124 indicating whether the request (i.e.the job 112 in the example shown in FIG. 1) is to be throttled. If nolocal traffic management policy 130 applies to a particular request, therequest is permitted to pass through to the next handler 116 in thehandler chain or to the network service 104, as appropriate.

In one particular configuration, the dynamic function based trafficcontroller 126 utilizes token buckets representing a measure of anavailable resource on the service host computer 102. When a request isreceived, a list of keys are generated that are associated with thecomputing resources needed to process the request. For each of the keys,the dynamic function based traffic controller 126 checks to determine ifa token bucket is associated with the key. If one is found, a token isremoved. If there are no tokens to remove (i.e. the token bucket isempty), the request will be throttled.

Token buckets consist of a maximum number of tokens in a bucket and atoken refresh rate. In real or near-real time, the dynamic functionbased traffic controller 126 receives the metrics 132. As discussedabove, the metrics 132 can be combined with the local traffic managementpolicy 130 to infer the adjustments that need to be made to the tokenbuckets in order to enforce the local traffic management policy 130. Forexample, if an increased time to process responses can be correlated tohigh memory utilization on the service host computer 102, the operatorof the network service 104 might want to define a local trafficmanagement policy 130 that throttles less important requests moreaggressively in the case of high memory utilization in order to keeplatencies low. Other configurations can also be utilized in addition toor as an alternative to the token buckets described above.

If the dynamic function based traffic controller 126 determines that aservice request is to be throttled, the request is rejected and aresponse 146 can be routed up the handler chain in a manner similar tothat described above to the service client 106 that transmitted theoriginal service request. In the example configuration shown in FIG. 1,for instance, an HTTP response 144 can be returned to the service client106 indicating that the HTTP request 108 was throttled. If the dynamicfunction based traffic controller 126 determines that the servicerequest is not to be throttled, the job 112 can be provided to the nexthandler 116 in the handler chain or directly to the network service 104if the handler 116 performing the throttling (i.e. the handler 116B inthe configuration shown in FIG. 1) is the last handler 116 in thehandler chain.

In one particular configuration, for example, the mechanism describedabove with regard to FIG. 1 can be utilized to linearly or non-linearlyreduce the total rate of requests processed by the network service 104as the utilization of the CPU or memory of the service host computer 102rises in a manner specified by the local traffic management policy 130.As another example, this mechanism can be utilized to adjust the allowedrequest rate for a specific operation that depends upon a cache in theservice host computer 102 as a function of the cache hit/miss rate. Asanother example, the mechanism described above can be utilized toprioritize access to a database or other resource utilized or providedby the service host computer 102 for a specific user or group of users.In yet another example, the mechanism described above can be utilized tothrottle requests for database writes more greatly than requests fordatabase reads, and to throttle new requests more than requests that arebeing retried. It should be appreciated that these examples are merelyillustrative and that other configurations can be utilized to throttleparticular classifications of requests as a function of the localtraffic management policy 130 and one or more real time metrics 132.

It should also be appreciated that while the dynamic function basedtraffic controller 126 and the local real time performance monitoringsystem 134 are shown in FIG. 1 as executing outside of the serviceframework 110, these components may be executed within the serviceframework 110 or within a handler 116 within the service framework 110in other configurations. Similarly, while the traffic classifier 120 isshown as illustrating within the handler 116B in FIG. 1, this componentcan also be executed outside of the handler 116B or outside the serviceframework 110 altogether in other configurations. The disclosedfunctionality can also be implemented within the network service 104 inother configurations in order to enable throttling based upon other dataaccessible to or maintained by the network service 104. Otherconfigurations can also be utilized. Additional details regarding themechanism shown in FIG. 1 for local function based dynamic trafficmanagement will be provided below with regard to FIGS. 2 and 5.

FIG. 2 is a flow diagram showing a routine 200 that illustrates aspectsof the operation of the mechanism shown in FIG. 1 for local functionbased dynamic traffic management for network services, according to oneconfiguration presented herein. It should be appreciated that thelogical operations described herein with respect to FIG. 2 and the otherfigures are implemented (1) as a sequence of computer implemented actsor program modules running on a computing system and/or (2) asinterconnected machine logic circuits or circuit modules within thecomputing system. The implementation of the various components describedherein is a matter of choice dependent on the performance and otherrequirements of the computing system.

Accordingly, the logical operations described herein are referred tovariously as operations, structural devices, acts, or modules. Theseoperations, structural devices, acts, and modules can be implemented insoftware, in firmware, in special purpose digital logic, and anycombination thereof. It should also be appreciated that more or feweroperations can be performed than shown in the FIGS. and describedherein. These operations can also be performed in parallel, or in adifferent order than those described herein.

The routine 200 begins at operation 202, where the policy definitiontool 128 provides a GUI for defining the local traffic management policy130. The routine 200 then proceeds from operation 204, where the localtraffic management policy 130 is received via the GUI and stored in alocation that is accessible to the dynamic function based trafficcontroller 126. For example, data defining the local traffic managementpolicy 130 can be stored locally on the service host computer 102. Asdiscussed above and in greater detail below with regard to FIG. 5, theGUI provided by the policy definition tool 128 provides functionalityfor enabling a user to graphically define a local traffic managementfunction. Other mechanisms can also be utilized in other configurationsto define the local traffic management policy 130.

From operation 204, the routine 200 proceeds to operation 206, where thehandler 116B that implements the traffic classifier 120 receives a job112. The routine 200 then proceeds from operation 206 to operation 208,where the traffic classifier 120 determines a classification 122 for thereceived job 122. As discussed above, the classification 122 for the job112 can be determined based upon the request attributes 114, themetadata 118 generated by the other handlers 116, and/or other dataavailable to the traffic classifier 122. Once the classification 122 hasbeen determined, the routine 200 proceeds from operation 208 tooperation 210.

At operation 210, the traffic classifier 120 calls the dynamic functionbased traffic controller 126 with the determined classification 122 forthe job 112. The routine 200 then proceeds to operation 212, where thedynamic function based traffic controller 126 determines whether tothrottle the job 112 based upon the local traffic management policy 130,the classification 122, and the relevant metrics 132 received from thelocal real time performance monitoring system 134. The routine 200 thenproceeds from operation 212 to operation 214.

If the job 112 is to be throttled, the routine 200 proceeds to operation216, where a response 146 can be passed back up the handler chain to theoriginating service client 106. If the job 112 is not to be throttled,the routine 200 proceeds to operation 218, where the job 112 can bepassed to the next handler 116 in the handler chain or to the callednetwork service 104, as appropriate. From operations 216 and 218, theroutine 200 proceeds back to operation 206, where the processesdescribed above can be repeated to throttle additional service requests.

It should be appreciated that the process illustrated in FIG. 2 anddescribed above can be implemented as a pipeline so that multiple jobs112 can be evaluated simultaneously. Moreover, it should be furtherappreciated that the process described above with regard to FIG. 2 canbe implemented utilizing multiple processor threads. For example, andwithout limitation, one processor thread can be executed that updatesthe buckets described above based upon the metrics received from thereal time performance monitoring system 134. Another processor threadcan be executed that utilizes the buckets, the local traffic managementpolicy 130, and the classification 122 to determine whether a job 112 isto be throttled. Other implementations can also be utilized in otherconfigurations.

FIG. 3 is a network services architecture diagram showing aspects of amechanism disclosed herein for distributed function based dynamictraffic management for network services, according to one configurationpresented herein. As shown in FIG. 3 and described briefly above, amechanism similar to that described above with regard to FIGS. 1 and 2can be utilized to perform distributed function based dynamic trafficmanagement. In this configuration, a number of service host computers102A-102N (which might be referred to below collectively as the “servicehost computers 102”), are operated together as a part of a host fleet302. Each of the service host computers 102 in the host fleet 302 can beconfigured in the manner described above with regard to FIGS. 1 and 2.In this example, however, the throttle rates for certain types ofservice requests can be set for all of the service host computers 102 inthe host fleet 302 rather than for only a single service host computer102.

In order to provide this functionality, a component on each of theservice host computers 102, such as the local real time performancemonitoring system 134, provides real or near-real time metrics132A-132N, respectively, to a distributed performance monitoring system134A. The distributed performance monitoring system 134A collects themetrics 132 from each of the service host computers 102 and makes themetrics 132 available to a dynamic function based traffic controller126A.

The metrics 132 shown in FIG. 3 can be collected in real or in near-realtime a manner similar to that described above with regard to FIGS. 1 and2 for collecting metrics specific to a particular service host computer102. In one configuration, the open source APACHE KHAFKA distributedmessaging system is utilized to route the metrics 132A-132C to thedistributed performance monitoring system 134A. Other types of messagingsystems can be utilized in other configurations.

A distributed traffic management policy 130A can be also definedutilizing a GUI provided by the policy definition tool 128 similar tothat described briefly above and in further detail below with regard toFIG. 5 for defining the local traffic management policy 130. Thedistributed traffic management policy 130A defines how service requestsare to be throttled on a fleet-wide basis.

The distributed function based traffic controller 126A utilizes thedistributed traffic management policy 130A and the metrics 132 providedby the distributed performance monitoring system 134A to dynamicallydetermine the throttle rates on a fleet-wide level. The distributedfunction based traffic controller 126A can then send update events304A-304C, respectively, to the service host computers 102 in the hostfleet 302 instructing the service hosts 102 to adjust the throttle ratefor certain classifications of requests. In one configuration, the opensource APACHE KHAFKA distributed messaging system is utilized to routethe update events 304A-304C to the service host computers 102 in thehost fleet 302. Other types of messaging systems can be utilized inother configurations.

The adjusted throttle rate can then be utilized by the dynamic functionbased traffic controller 126 executing on each service host computer 102in the manner described above with regard to FIGS. 1 and 2 to throttleincoming requests. Additional details regarding the operation of thesystem shown in FIG. 3 for distributed function based dynamic trafficmanagement for network services will be provided below with regard toFIG. 4.

FIG. 4 is a flow diagram showing a routine 400 that illustrates aspectsof the operation of the mechanism shown in FIG. 3 for distributedfunction based dynamic traffic management for network services,according to one configuration presented herein. The routine 400 beginsat operation 402, where the service host computers 102 in the host fleet302 send metrics 132 to the distributed performance monitoring system134A. In one configuration, the operator of the network service 104 canspecify the particular metrics 132 that are routed to the distributedperformance monitoring system 134. The metrics 132 can also betransmitted periodically, such as once every 500 ms or other timeperiod.

From operation 402, the routine 400 proceeds to operation 404, where thedynamic function based traffic controller 126A obtains the metrics 132from the distributed performance monitoring system 134A. The routine 400then proceeds to operation 406, where the dynamic function based trafficcontroller 126A creates update events 304 based upon the metrics 132 andthe distributed traffic management policy 130A. As discussed above, theupdate events 304 can specify updated throttle rates to be utilized bythe dynamic function based traffic controller 126 executing on each ofthe service host computers 102 in the host fleet 302.

The routine 400 then proceeds to operation 408 where the dynamicfunction based traffic controller 126A transmits the update events 304to the service host computers 102 in the host fleet 302. As discussedabove, a distributed messaging system can be utilized in someconfigurations to transmit the metrics 132 to the distributedperformance monitoring system 134A and to transmit the update events 304to the service host computers 102 in the host fleet 302.

From operation 408, the routine 400 proceeds to operation 410, where theservice host computers 102 in the host fleet 302 utilize the updateevents 304 to adjust the throttle rates utilized by the dynamic functionbased traffic controller 126. In the configuration described above, thetoken buckets can be adjusted based upon the throttle rates specific bythe update events 304. The throttle rates can be adjusted in other waysin other configurations. From operation 410, the routine 400 proceedsback to operation 402, where the operations described above can berepeated.

FIG. 5 is a GUI diagram showing aspects of the configuration of oneillustrative GUI 502 for defining a local traffic management policy 130or a distributed traffic management policy 130A, according to oneconfiguration disclosed herein. In the specific example shown in FIG. 5,the GUI 502 is being utilized to define a local network trafficmanagement policy 130 that includes a local service traffic managementfunction.

As discussed above, the local service traffic management function is apolynomial function that takes as input the value of one or more metrics132 relating to the execution of a network service 104 (e.g. CPUutilization, memory utilization, etc.), and provides as output athrottle rate for a particular classification 122 of service requests.The throttle rate defines the rate at which service requests having aparticular classification 122 are to be throttled.

In the configuration shown in FIG. 5, the GUI 502 provides several userinterface elements 502 and 504. The user interface element 502 providesfunctionality for displaying the values of one or more metrics 132 inreal or near-real time. For example, a user interface (not shown in FIG.5) can be provided through which a user can select the metrics 132 to beshown in the user interface element 502. In the example shown in FIG. 5,for instance, the user has selected a metric 132 relating to heap usageby a VM executing on the service host computer 102.

A user interface control 506 is also provided in the configuration shownin FIG. 5 which, when selected, will begin playback of the values forthe selected metric 132 in real or near-real time. The X-axis of theuser interface control 502 represents time, while the Y-axis of the userinterface element 502 represents the value of the presented metric 132,or metrics 132. In one configuration, the most recently obtained valuesfor the metric 132 will be presented on the right side of the userinterface element 502. These values will move to the left as new valuesare presented. Accordingly, the values on the right side of the userinterface element 502 for the metric 132 are the most recently sampledvalues, while the values presented on the left side of the userinterface element 502 are older values. The user interface control 506can also be selected in order to stop playback of the values for themetric 132 in the user interface element 502.

As discussed above with regard to FIG. 1, the policy definition tool 128can be implemented as a network accessible web site in someconfigurations. In these configurations, a web socket can be establishedwith the service host computer 102 to enable the metrics 132 to betransmitted to the policy definition tool 128 and presented in the GUI500 in real or near-real time. The web socket can also be utilized totransmit commands received through the GUI 500, such as the definitionof the local service traffic management function, described below. Inthis manner, the impact of changes made to the local traffic managementpolicy 130 through the GUI 500 can be viewed in real or near-real time.A similar mechanism can be utilized when the policy definition tool 128is implemented as a stand-alone application or in another manner.

A user interface control 508 is also presented in the illustrative GUI500 shown in FIG. 5 for automatically adjusting the scale used for theY-axis of the user interface element 502. In the example shown in FIG.5, for instance, the user interface control 508 has been selected and,accordingly, the Y-axis of the user interface element 502 has beenscaled to include only the range of values between the displayed minimumand maximum values for the displayed metric 132. The user interfacecontrol 508 can be de-selected to turn off the automatic adjustment ofthe scale used for the Y-axis of the user interface element 502 in thismanner.

In the example shown in FIG. 5, a user interface element 504 is alsoprovided through which the operator of the network service 104 candefine a curve 510 representing the local service traffic managementfunction. As discussed above, the input of the local service trafficmanagement function are values for a metric 132 and the output of thefunction is a throttle rate for a particular classification 122 ofservice requests.

In order to begin the process of creating a local service trafficmanagement function, the user first utilizes the user interface controls516A-516D to specify one or more input properties and the user interfacecontrols 518A-518B to specify one or more output properties of the localservice traffic management function. In particular, the user interfacecontrol 516A can be utilized to specify the metric 132 that is to beutilized as the input to the local service traffic management function.In the example shown in FIG. 5, for instance, the user has specified ametric 132 relating to the usage of heap memory by a VM executing on aservice host computer 102. As mentioned above, the specified metric 132is represented on the X-axis of the user interface element 504.

The user interface control 516B can be utilized to specify whether theactual values for the metric 132 or the rate of change of the values ofthe metric 132 are to be utilized as input to the function. The userinterface controls 516C and 516D can be utilized, respectively, tospecify the minimum and maximum values for the metric 132 to which thedefined function is to apply.

The user interface controls 518A and 518B can be utilized to specify thetype of requests that are to be throttled by the defined local servicetraffic management function (i.e. the classification 122 of requests towhich the defined function applies). The user interface controls 518Cand 518D can be utilized, respectively, to specify the minimum andmaximum values for output of the specified function.

Once the user has specified the input and output properties describedabove, the user can define a curve 510 representing the local servicetraffic management function in the user interface element 504. Inparticular, the user can utilize an appropriate input device, such as amouse, touchscreen, or touch-sensitive trackpad, to define the curve510. The user can also be permitted to provide control points 512A-512Ndefining the curve, to select and “drag” the control points 512A-512Nusing the cursor 514 to define the curve 510 and, potentially, tospecify the contour of the curve 510 in different ways. Data definingthe curve 510 can then be saved in the local traffic management policy130 for consumption by the dynamic function based traffic controller126. In one configuration, the user interface element 504 also includesshading 520 that provides an indication of the location on the curve 510of the current value for the corresponding metric 132. The shading 520can be updated in real or near-real time as the current value of therepresented metric 132 changes.

In the example shown in FIG. 5, the user has defined a curve 510 thatdefines a function for reducing the allowed CPU requests per secondbased upon the usage of heap memory by a VM. When the usage of the heapmemory approaches 2 GB, no CPU requests will be permitted. In thisregard, it should be appreciated that the curve 510 shown in FIG. 5 ismerely illustrative and that other types of curves 510 can be definedusing the GUI 500 shown in FIG. 5.

It should also be appreciated that the GUI 500 shown in FIG. 5 is merelyillustrative and that functionality can be provided in otherconfigurations for specifying other properties of a local servicetraffic management function and/or for viewing the real time metrics 132described above. Other user interface elements, controls, and layoutscan be utilized in other configurations. Other mechanisms can also oralternately be provided for permitting the definition of a local servicetraffic management function. Additionally, and as mentioned above withregard to FIGS. 3 and 4, a GUI similar to that shown in FIG. 5 can alsobe provided for defining a polynomial function based distributed trafficmanagement policy 130A.

FIG. 6 is a network diagram showing aspects of a distributed computingenvironment that can be utilized to provide an operating environment forthe various technologies disclosed herein. In particular, thedistributed computing environment shown in FIG. 6 can provide a suitablecomputing environment in which the various technologies described hereincan be implemented. The distributed computing environment shown in FIG.6 is configured using a service-oriented architecture (“SOA”) in oneimplementation. Other configurations can also be utilized.

The distributed computing environment shown in FIG. 6 can providecomputing resources for executing distributed programs on a permanent oran as-needed basis. The computing resources provided by the distributedcomputing environment can include various types of resources, such asdata processing resources, data storage resources, data communicationresources, and the like. Each type of computing resource can begeneral-purpose or can be available in a number of specificconfigurations. For example, data processing resources can be availableas virtual machine instances. The instances can be configured to executeprograms, including web servers, application servers, media servers,database servers, and other types of components such as those describedin detail above. Data storage resources can include file storagedevices, block storage devices, and the like. Each type or configurationof computing resource can be available in different sizes, such as largeresources, consisting of many processors, large amounts of memory,and/or large storage capacity, and small resources consisting of fewerprocessors, smaller amounts of memory, and/or smaller storage capacity.

The computing resources provided by the distributed computingenvironment shown in FIG. 6 are furnished in one configuration by servercomputers and other components operating in one or more data centers602A-602D (which might be referred to herein singularly “as a datacenter 602” or collectively as “the data centers 602”). The data centers602 are facilities utilized to house and operate computer systems andassociated components for providing a distributed computing environment.The data centers 602 can include redundant and backup power,communications, cooling, and security systems. The data centers 602 canalso be located in geographically disparate locations. One illustrativeconfiguration for a data center 602 that implements aspects of thetechnologies disclosed herein for local and distributed function baseddynamic traffic management for network services will be described belowwith regard to FIG. 7.

Users of the distributed computing environment illustrated in FIG. 6 canaccess the computing resources provided by the data centers 602 over awide-area network (“WAN”) 604. Although a WAN 604 is illustrated in FIG.6, it should be appreciated that a local-area network (“LAN”), theInternet, or any other networking topology known in the art thatconnects the data centers 602 to computing devices utilized by remotecustomers and other users can be utilized. It should also be appreciatedthat combinations of such networks can also be utilized.

The distributed computing environment can provide various interfacesthrough which aspects of its operation can be configured. For instance,various APIs can be exposed by components operating in the distributedcomputing environment shown in in FIG. 6 for configuring various aspectsof its operation and for utilizing various aspects of the functionalitythat it provides. Other mechanisms for configuring the operation ofcomponents in the distributed computing environment and for utilizingthese components can also be utilized.

According to configurations disclosed herein, the capacity of resourcesprovided by the distributed computing environment can be scaled inresponse to demand. In this regard, scaling refers to the process ofinstantiating (which might also be referred to herein as “launching” or“creating”) or terminating (which might also be referred to herein as“de-scaling”) instances of computing resources in response to demand.Auto scaling is one mechanism for scaling computing resources inresponse to increases or lulls in demand for the resources. Additionaldetails regarding the functionality provided by the data centers 602will be provided below with regard to FIG. 7.

FIG. 7 is a computing system diagram that illustrates a configurationfor a data center 602A that can be utilized to implement the varioustechnologies described herein. The example data center 602A shown inFIG. 7 includes several server computers 702A-702F (which might bereferred to herein singularly as “a server computer 702” or in theplural as “the server computers 702”) for providing computing resourcesfor executing distributed programs, such as those described in detailabove.

The server computers 702 can be tower, rack-mount, or blade servercomputers configured appropriately for executing a distributed programor providing other functionality. The data center 602A shown in FIG. 7also includes one or more server computers 702, such as the servercomputer 702F, that execute software components for providing aspects ofthe functionality described above. In particular, the server computer702F can execute the service framework 110, the dynamic function basedtraffic controller 126, and the local real time performance monitoringsystem 134 described in detail above. The server computer 702F can alsoexecute other software components not specifically shown in FIG. 7.

In the example data center 602A shown in FIG. 7, an appropriate LAN 704is utilized to interconnect the server computers 702. The LAN 704 isalso connected to the WAN 604 illustrated in FIG. 6. It should beappreciated that the network topology illustrated in FIGS. 6 and 7 hasbeen greatly simplified for discussion purposes and that many morenetworks and networking devices can be utilized to interconnect thevarious computing systems disclosed herein. Appropriate load balancingdevices or software modules can also be utilized for balancing a loadbetween each of the data centers 602, between each of the servercomputers 702 in each data center 602, or between virtual machineinstances executing within the distributed computing environment.

It should also be appreciated that the data center 602A described inFIG. 7 is merely illustrative and that other implementations can beutilized. Additionally, it should be appreciated that the disclosedfunctionality can be implemented in software, hardware or a combinationof software and hardware. Additional details regarding one computerarchitecture for implementing the server computers 702 will be describedbelow with regard to FIG. 8.

FIG. 8 shows an example computer architecture for a computer 800 capableof executing the program components described herein. The computerarchitecture shown in FIG. 8 illustrates a conventional server computer,workstation, desktop computer, laptop, tablet, network appliance,e-reader, smartphone, or other computing device, and can be utilized toexecute any aspects of the software components presented herein, such asthose described as executing within the data centers 602A-602D, on theserver computers 602A-602F, or on any other computing system mentionedherein.

The computer 800 includes a baseboard, or “motherboard,” which is aprinted circuit board to which a multitude of components or devices canbe connected by way of a system bus or other electrical communicationpaths. In one illustrative configuration, one or more CPUs 802 operatein conjunction with a chipset 804. The CPUs 802 can be programmableprocessors that perform arithmetic and logical operations necessary forthe operation of the computer 800.

The CPUs 802 perform operations by transitioning from one discrete,physical state to the next through the manipulation of switchingelements that differentiate between and change these states. Switchingelements generally include electronic circuits that maintain one of twobinary states, such as flip-flops, and electronic circuits that providean output state based on the logical combination of the states of one ormore other switching elements, such as logic gates. These basicswitching elements can be combined to create more complex logiccircuits, including registers, adders-subtractors, arithmetic logicunits, floating-point units, and the like.

The chipset 804 provides an interface between the CPUs 802 and theremainder of the components and devices on the baseboard. The chipset804 provides an interface to a RAM 806, used as the main memory in thecomputer 800. The chipset 804 can further provide an interface to acomputer-readable storage medium such as a read-only memory (“ROM”) 808or non-volatile RAM (“NVRAM”) for storing basic routines that help tostartup the computer 800 and to transfer information between the variouscomponents and devices. The ROM 808 or NVRAM can also store othersoftware components necessary for the operation of the computer 800 inaccordance with the configurations described herein.

The computer 800 can operate in a networked environment using logicalconnections to remote computing devices and computer systems through anetwork, such as the local area network 704. The chipset 804 can includefunctionality for providing network connectivity through a NIC 810, suchas a gigabit Ethernet adapter. The NIC 810 is capable of connecting thecomputer 800 to other computing devices over the network 704. It shouldbe appreciated that multiple NICs 810 can be present in the computer800, connecting the computer to other types of networks and remotecomputer systems.

The computer 800 can be connected to a mass storage device 812 thatprovides non-volatile storage for the computer. The mass storage device812 can store system programs, application programs, other programmodules, and data, which have been described in greater detail herein.The mass storage device 812 can be connected to the computer 800 througha storage controller 814 connected to the chipset 804. The mass storagedevice 812 can consist of one or more physical storage units. Thestorage controller 814 can interface with the physical storage unitsthrough a serial attached SCSI (“SAS”) interface, a serial advancedtechnology attachment (“SATA”) interface, a fiber channel (“FC”)interface, or other type of interface for physically connecting andtransferring data between computers and physical storage units.

The computer 800 can store data on the mass storage device 812 bytransforming the physical state of the physical storage units to reflectthe information being stored. The specific transformation of physicalstate can depend on various factors, in different implementations ofthis description. Examples of such factors can include, but are notlimited to, the technology used to implement the physical storage units,whether the mass storage device 812 is characterized as primary orsecondary storage, and the like.

For example, the computer 800 can store information to the mass storagedevice 812 by issuing instructions through the storage controller 814 toalter the magnetic characteristics of a particular location within amagnetic disk drive unit, the reflective or refractive characteristicsof a particular location in an optical storage unit, or the electricalcharacteristics of a particular capacitor, transistor, or other discretecomponent in a solid-state storage unit. Other transformations ofphysical media are possible without departing from the scope and spiritof the present description, with the foregoing examples provided only tofacilitate this description. The computer 800 can further readinformation from the mass storage device 812 by detecting the physicalstates or characteristics of one or more particular locations within thephysical storage units.

In addition to the mass storage device 812 described above, the computer800 can have access to other computer-readable storage media to storeand retrieve information, such as program modules, data structures, orother data. It should be appreciated by those skilled in the art thatcomputer-readable storage media can be any available media that providesfor the storage of non-transitory data and that can be accessed by thecomputer 800.

By way of example, and not limitation, computer-readable storage mediacan include volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology. Computer-readable storage mediaincludes, but is not limited to, RAM, ROM, erasable programmable ROM(“EPROM”), electrically-erasable programmable ROM (“EEPROM”), flashmemory or other solid-state memory technology, compact disc ROM(“CD-ROM”), digital versatile disk (“DVD”), high definition DVD(“HD-DVD”), BLU-RAY, or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium that can be used to store the desired information ina non-transitory fashion.

The mass storage device 812 can store an operating system 816 utilizedto control the operation of the computer 800. In one configuration, theoperating system is the LINUX operating system. In anotherconfiguration, the operating system is the WINDOWS® SERVER operatingsystem from MICROSOFT Corporation. According to a further configuration,the operating system is the UNIX operating system. It should beappreciated that other operating systems can also be utilized. The massstorage device 812 can also store other programs 820 and data utilizedby the computer 800, such as the various software components and datadescribed above. The mass storage device 812 can also store otherprograms and data not specifically identified herein.

In one configuration, the mass storage device 812 or othercomputer-readable storage media is encoded with computer-executableinstructions which, when loaded into the computer 800, transforms thecomputer from a general-purpose computing system into a special-purposecomputer capable of implementing the configurations described herein.These computer-executable instructions transform the computer 800 byspecifying how the CPUs 802 transition between states, as describedabove. According to one configuration, the computer 800 has access tocomputer-readable storage media storing computer-executable instructionswhich, when executed by the computer 800, perform the routines 200 and400, described above with regard to FIGS. 2 and 4, and the otheroperations described with reference to the other FIGS.

The computer 800 can also include an input/output controller 818 forreceiving and processing input from a number of input devices, such as akeyboard, a mouse, a touchpad, a touch screen, an electronic stylus, orother type of input device. Similarly, the input/output controller 818can provide output to a display, such as a computer monitor, aflat-panel display, a digital projector, a printer, a plotter, or othertype of output device. It will be appreciated that the computer 800might not include all of the components shown in FIG. 8, can includeother components that are not explicitly shown in FIG. 8, or can utilizean architecture completely different than that shown in FIG. 8.

Based on the foregoing, it should be appreciated that technologies forlocal and distributed function based dynamic traffic management fornetwork services have been presented herein. Although the subject matterpresented herein has been described in language specific to computerstructural features, methodological acts, and computer readable media,it is to be understood that the invention defined in the appended claimsis not necessarily limited to the specific features, acts, or mediadescribed herein. Rather, the specific features, acts, and mediums aredisclosed as example forms of implementing the claims.

The subject matter described above is provided by way of illustrationonly and should not be construed as limiting. Furthermore, the claimedsubject matter is not limited to implementations that solve any or alldisadvantages noted in any part of this disclosure. Variousmodifications and changes can be made to the subject matter describedherein without following the example configurations and applicationsillustrated and described, and without departing from the true spiritand scope of the present invention, which is set forth in the followingclaims.

What is claimed is:
 1. A computer-implemented method for management ofservice requests directed to a network service, the method comprising:receiving, at a service host computer, a service request directed to thenetwork service, wherein the network service is executing locally at theservice host computer; responsive to receiving the service request,determining a classification of the service request; determining whetherthe service request is to be processed by the network service based uponthe classification of the service request, one or more real time metricsassociated with the network service, and a local traffic managementpolicy, wherein the local traffic management policy defines a polynomialtraffic management function having an input comprising a value of atleast one of the one or more real time metrics and an output defining athrottle rate at which to throttle service requests of theclassification; rejecting the service request responsive to determiningthat the service request is not to be processed by the network service;and causing the service request to be processed by the network serviceresponsive to determining that the service request is to be processed bythe network service.
 2. The computer-implemented method of claim 1,wherein the classification of the service request is determined based,at least in part, on one or more attributes of the service request. 3.The computer-implemented method of claim 1, wherein the classificationof the service request is determined based, at least in part, uponmetadata associated with the service request generated by one or morehandlers within a service framework executing on the service hostcomputer.
 4. The computer-implemented method of claim 1, furthercomprising a graphical user interface for defining the polynomialtraffic management function.
 5. The computer-implemented method of claim4, wherein the graphical user interface comprises a user interfaceelement for defining a curve representing the polynomial trafficmanagement function.
 6. The computer-implemented method of claim 1,further comprising: providing the one or more real time metricsassociated with the network service to a distributed performancemonitoring system; receiving one or more update events from a dynamicfunction based traffic controller in communication with the distributedperformance monitoring system; and adjusting the throttle rate based, atleast in part, upon the one or more update events.
 7. Thecomputer-implemented method of claim 6, wherein the dynamic functionbased traffic controller is configured to compute the throttle ratebased, at least in part, upon a distributed traffic management policy,the one or more real time metrics received from the service hostcomputer, and real time metrics received from at least one other servicehost computer.
 8. A non-transitory computer-readable storage mediumhaving computer-executable instructions stored thereupon which, whenexecuted by a service host computer, cause the service host computer to:obtain a request directed to a network service, wherein the networkservice is executing locally at the service host computer; determine aclassification of the request; determine whether the request is to beprocessed by the network service based upon the classification of therequest, one or more metrics associated with the network service, and alocal traffic management policy, wherein the local traffic managementpolicy defines a polynomial traffic management function having an inputcomprising a value of at least one of the one or more metrics and anoutput defining a throttle rate at which to throttle requests having theclassification; cause the request to be rejected responsive todetermining that the request is not to be processed by the networkservice; and cause the request to be processed by the network serviceresponsive to determining that the request is to be processed by thenetwork service.
 9. The non-transitory computer-readable storage mediumof claim 8, wherein determining whether the request is to be processedby the network service is determined by a dynamic function based trafficcontroller executing in conjunction with at least one handler in aservice framework executing on a same service host computer as thenetwork service.
 10. The non-transitory computer-readable storage mediumof claim 9, wherein there is a plurality of handlers executed in aspecified order.
 11. The non-transitory computer-readable storage mediumof claim 10, wherein a first handler of the plurality of handlers addsmetadata to the service request and wherein the service request istransmitted to the network service for processing in response tocompletion of execution of a second handler, wherein the second handleris last in the specified order.
 12. The non-transitory computer-readablestorage medium of claim 8, wherein the one or more metrics are sampledat a predefined rate.
 13. The non-transitory computer-readable storagemedium of claim 8, having further computer-executable instructionsstored thereupon to provide a graphical user interface for defining thepolynomial traffic management function, the graphical user interfacecomprising a user interface element for defining a curve representingthe polynomial traffic management function.
 14. The non-transitorycomputer-readable storage medium of claim 8, having furthercomputer-executable instructions stored thereupon to: provide the one ormore metrics associated with the network service to a distributedperformance monitoring system; receive one or more update events from adynamic function based traffic controller in communication with thedistributed performance monitoring system; and adjust the throttle ratebased, at least in part, upon the one or more update events.
 15. Anapparatus, comprising: one or more processors; and at least onenon-transitory computer-readable storage medium having instructionsstored thereupon which, when executed by the one or more processors,cause the processors to receive a request directed to a network service,determine a classification of the request, determine whether the requestis to be processed by the network service based upon the classificationof the request, one or more metrics associated with the network service,and a local traffic management policy, wherein the local trafficmanagement policy defines a polynomial traffic management functionhaving an input comprising a value of at least one of the one or moremetrics and an output defining a throttle rate at which to throttlerequests having the classification, cause the request to be rejectedresponsive to determining that the request is not to be processed by thenetwork service, and cause the request to be processed by the networkservice responsive to determining that the request is to be processed bythe network service.
 16. The apparatus of claim 15, wherein determiningwhether the request is to be processed by the network service isdetermined by a dynamic function based traffic controller executing inconjunction with a handler in a service framework executing on a servicehost computer executing the network service.
 17. The apparatus of claim15, wherein the non-transitory computer-readable storage medium hasfurther instructions stored thereupon to provide a graphical userinterface for defining the polynomial traffic management function, thegraphical user interface comprising a user interface element fordefining a curve representing the polynomial traffic managementfunction.
 18. The apparatus of claim 15, wherein the classification ofthe request is determined based, at least in part, upon metadataassociated with the request generated by one or more handlers within aservice framework executing on a service host computer executing thenetwork service.
 19. The apparatus of claim 15, wherein thenon-transitory computer-readable storage medium has further instructionsstored thereupon to: provide the one or more metrics associated with thenetwork service to a distributed performance monitoring system; receiveone or more update events from a dynamic function based trafficcontroller in communication with the distributed performance monitoringsystem; and adjust the throttle rate based, at least in part, upon theone or more update events.
 20. The apparatus of claim 19, wherein thedynamic function based traffic controller is configured to compute thethrottle rate based, at least in part, upon a distributed trafficmanagement policy and metrics received from a plurality of service hostcomputers.